no, it’s very boring, but you cant do this.
you can on a linked stereo pair, but that’s it.
you CAN add a keyframe to all tracks if they are selected, and you use the add audio keyframe command (option apple k, is it?)
but then you have to drag each one manually.
best is to keyframe one track, copy & paste attributes into others.
and simples way to do that is: keyframe top track,
select clip, copy, paste attributes, you get a warning about only copying first tracks attributes, you say yes, and continue.
still very boring!
sometime i get fed up and simply add a transition!
nick